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Analog Devices Inc./Maxim Integrated MAX1557ETB
- Part No.:
- MAX1557ETB
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
MAX1557ETB.pdf
- Description:
- IC REG BUCK ADJ 600MA 10TDFN
- Quantity:
- Payment:
- Shipping:
Inventory:437
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Product details
Overview
The MAX1557ETB from Maxim Integrated is a synchronous step-down DC-DC converter delivering up to 600mA output current with pin-selectable 1.0V, 1.3V, or 1.5V fixed outputs-or adjustable down to 0.75V-optimized for single-cell Li-ion and 3-cell alkaline/NiMH battery-powered portable electronics. It features 16µA quiescent current, 1MHz PWM switching, and 27µA dropout quiescent current.
For engineers reviewing the MAX1557ETB datasheet, MAX1557ETB pinout, MAX1557ETB application, or MAX1557ETB equivalent, key selection criteria include guaranteed 600mA load capability, TDFN-EP (3mm × 3mm) package thermal performance, voltage positioning for CPU core rail transient response, and soft-start capacitor sizing for inrush control in handheld instruments and digital cameras.
Technical Context
The MAX1557ETB employs a fixed-frequency (1MHz), current-mode PWM control architecture with internal slope compensation and open-loop comparator-based regulation. Its proprietary topology enables high efficiency across light-to-full loads by automatically entering pulse-skipping mode below ~10mA, maintaining 16µA IQ.
It integrates a low-RDS(ON) p-channel high-side switch (0.42Ω typ at 2.6V) and n-channel synchronous rectifier, eliminating external Schottky diodes. Voltage positioning is implemented via a defined load-regulation slope (−0.75% to −2.75% over 600mA load range), minimizing transient droop during CPU load steps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 600mA guaranteed - supports sustained operation of baseband processors and image sensors in portable devices. |
| Input Voltage Range | 2.6V to 5.5V - compatible with fully discharged 3-cell alkaline (≈2.7V) and 1-cell Li-ion (2.7–4.2V) batteries. |
| Quiescent Current | 16µA typical - extends battery runtime in standby modes of PDAs and smart phones. |
| Switching Frequency | 1MHz ±10% - enables use of tiny 3.3µH/4.7µH inductors and compact ceramic capacitors (e.g., 22µF X5R). |
| Dropout Quiescent Current | 27µA typical - maintains ultra-low power draw when VIN drops near VOUT, maximizing usable battery capacity. |
| Shutdown Current | 0.1µA - ensures negligible drain during system sleep, critical for always-on sensor nodes. |
| Output Accuracy | ±1.75% at 300mA, ±2.75% at 600mA (TA = −40°C to +85°C) - meets tight tolerance requirements for FPGA I/O rails and DSP cores. |
Pinout & Package
MAX1557ETB is housed in a thermally enhanced 10-pin TDFN-EP package (3mm × 3mm, 0.8mm height) with exposed paddle soldered to PCB ground plane for optimal thermal dissipation (θJA ≈ 41°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN | Low-current input supply | Accepts 2.6V–5.5V; bypassed externally; feeds bias circuitry only. |
| 2 GND | Analog ground reference | Must be star-connected to PGND at output capacitor; referenced by error amplifier and SS ramp. |
| 3 SS | Soft-start timing node | Exponential ramp generator; requires 1000pF to GND for standard startup; discharge path enabled in shutdown. |
| 4 OUT | Feedback sense input | Connects directly to regulated output; internal resistor divider active even in shutdown. |
| 5 SHDN | Digital enable control | Active-low logic input; pulls to GND for 0.1µA shutdown; tied to IN for always-on operation. |
| 6 D2 | Output voltage select bit | Logic-level input (0=GND, 1=IN); selects 1.0V/1.3V/1.5V/adjustable per truth table. |
| 7 PGND | Power ground return | High-current return path for LX switch and output capacitor; must be low-inductance connection to exposed paddle. |
| 8 LX | Switch node | Drain connection of internal p-channel and n-channel MOSFETs; drives external inductor; high-impedance in shutdown. |
| 9 INP | High-current input supply | Main power path for switching stage; requires 10µF ceramic bypass to PGND; connected directly to IN in MAX1557 layout. |
| 10 D1 | Output voltage select bit | Logic-level input (0=GND, 1=IN); pairs with D2 to configure output per Table 1. |
Key Features
| Feature | Design Value |
|---|---|
| Voltage positioning load line | Guarantees ≤1.0% transient droop during 20mA→600mA load steps-critical for stable CPU core voltage under dynamic workloads. |
| Synchronous rectification | Eliminates external Schottky diode; reduces conduction loss by >30% vs. asynchronous buck at 600mA, improving full-load efficiency to 95%. |
| Adjustable soft-start | Configurable ramp time (e.g., 1ms with 1000pF) prevents input current overshoot into high-impedance Li-ion cells or alkaline batteries. |
| 100% duty-cycle dropout | Enables seamless transition from regulation to pass-through as battery discharges below VOUT, extending usable runtime by up to 15%. |
| Thermal shutdown protection | Activates at +160°C with 15°C hysteresis; disables both MOSFETs to prevent damage during sustained overload or poor heatsinking. |
Applications
| Smartphone Application Processor Core Rail | Digital Camera Image Sensor Bias |
|---|---|
Use Scenario: Powering ARM Cortex-A series application processors requiring tightly regulated 1.0V–1.3V core voltage with fast transient response during burst-mode video capture. IC Role / Device Role / Timing Role: Primary synchronous buck regulator supplying CPU core domain; implements voltage positioning to suppress load-step droop. Use Value: Delivers ≤1.0% output deviation during 100mA→600mA transients (20μs rise time), preventing processor reset or clock instability during frame processing. | Use Scenario: Providing clean, low-noise 1.5V bias to CMOS image sensors in compact digital cameras where EMI-sensitive analog pixel readout occurs. IC Role / Device Role / Timing Role: High-efficiency, low-ripple DC-DC converter with 1MHz fixed-frequency operation enabling small LC filter footprint. Use Value: Achieves <15mVpp output ripple with 22µF X5R ceramic capacitor, reducing sensor pattern noise and improving SNR by ≥3dB. |
| Hand-Held Medical Instrument LCD Backlight Driver Supply | PDA Baseband Modem Power Rail |
Use Scenario: Generating stable 1.3V supply for LED driver ICs powering transflective LCD backlights in battery-operated glucose meters and pulse oximeters. IC Role / Device Role / Timing Role: Compact, low-quiescent-current step-down converter supporting long shelf-life and intermittent usage patterns. Use Value: 16µA IQ and 0.1µA shutdown current enable >5-year shelf life on primary alkaline cells; 27µA dropout IQ preserves final 10% battery capacity. | Use Scenario: Delivering 1.0V at up to 600mA to GSM/UMTS baseband modems during RF transmission bursts in legacy PDAs. IC Role / Device Role / Timing Role: High-current, thermally robust buck converter with exposed paddle for reliable operation in confined plastic enclosures. Use Value: 3mm × 3mm TDFN-EP package with θJA = 41°C/W sustains 600mA continuous output without derating at +70°C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 3MHz switching frequency; 400mA max output; 2.05V–6.0V input; no voltage positioning. | Better suited for space-constrained apps needing smaller inductors; less effective for CPU core rails with large load transients. | Select when board area is critical and load steps are <200mA; avoid for high-dI/dt processor rails. |
| RT8059GJ6 | 2.5V–5.5V input; 600mA output; 1.5MHz switching; no integrated soft-start capacitor timing. | Requires external RC soft-start network; lacks voltage positioning slope; higher 25µA IQ in dropout. | Choose for cost-sensitive designs where soft-start timing flexibility is needed and transient performance is secondary. |
Compared with TPS62231DRYR and RT8059GJ6, the MAX1557ETB provides superior load-transient suppression via voltage positioning and lower dropout IQ-making it preferred for battery-powered systems where runtime and stability under dynamic loads are prioritized over minimal footprint.
Availability
MAX1557ETB is available at Aetrix Electronics and suitable for smartphone application processor core rails, digital camera image sensor bias supplies, hand-held medical instrument LCD backlight drivers, and PDA baseband modem power rails requiring stable component supply across extended production lifecycles.
Supply support for MAX1557ETB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX1557ETB belongs to Maxim's ultra-low-IQ synchronous buck converter product line, designed specifically for extending battery life in portable electronics while maintaining fast transient response for digital loads like CPUs and image sensors.
FAQ
What is the maximum continuous output current of the MAX1557ETB?
The MAX1557ETB guarantees 600mA continuous output current across the full operating temperature range (−40°C to +85°C). This rating is validated with proper PCB layout, adequate copper pour on the exposed paddle, and recommended 4.7µH inductor with ≥800mA saturation current. Derating applies above +70°C ambient per the 24.4mW/°C thermal derating curve.
Does the MAX1557ETB require an external Schottky diode?
No, the MAX1557ETB does not require an external Schottky diode. It integrates both a p-channel high-side switch and an n-channel synchronous rectifier, enabling full synchronous rectification. This eliminates conduction losses associated with external diodes and improves efficiency-especially at medium to high loads-while reducing component count and board area.
How is the output voltage selected on the MAX1557ETB?
The MAX1557ETB output voltage is selected using two logic inputs: D1 (pin 10) and D2 (pin 6). Driving these pins to GND (0) or IN (1) configures fixed outputs of 1.0V, 1.3V, or 1.5V per the truth table in the datasheet. Setting both D1 and D2 to GND enables adjustable mode, where an external resistor divider on the OUT pin sets VOUT from 0.75V to VIN.
What is the purpose of the SS pin on the MAX1557ETB?
The SS (soft-start) pin on the MAX1557ETB controls the output voltage ramp-up time to prevent input current overshoot during startup. A capacitor (typically 1000pF) connected from SS to GND sets the exponential ramp time constant (≈CSS × 200kΩ). The SS pin is internally discharged through a 200Ω resistor during shutdown, ensuring controlled turn-off behavior.
Can the MAX1557ETB operate with a 2.6V input and 1.5V output?
Yes, the MAX1557ETB can operate with a 2.6V input and 1.5V output. Its input voltage range is 2.6V to 5.5V, and its output is adjustable from 0.75V to VIN. At light loads, it maintains regulation efficiently via pulse-skipping mode; at heavy loads near dropout, it operates in 100% duty cycle with only 27µA quiescent current-ensuring stable 1.5V output even as the battery discharges to 2.6V.
MAX1557ETB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.75V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 600mA
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-TDFN-EP (3x3)
MAX1557ETB FAQ
1.How can I place an order for MAX1557ETB through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1557ETB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX1557ETB reliable?
The price and inventory of MAX1557ETB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1557ETB is usually 5 days.
3.What payment methods are accepted for MAX1557ETB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1557ETB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1557ETB?
MAX1557ETB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1557ETB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX1557ETB?
For technical support, including MAX1557ETB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1557ETB requirements.
6.How does Aetrix verify that MAX1557ETB is sourced from the original manufacturer or authorized distributors?
All MAX1557ETB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX1557ETB meets industry standards.
7.What is the process for return or replacement of MAX1557ETB?
All MAX1557ETB units undergo pre-shipment inspection (PSI). If there is an issue with MAX1557ETB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX1557ETB part is unused and in its original packaging.
Return procedure for MAX1557ETB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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